Various animals, such as beef cattle, dairy cattle, horses, sheep, goats, and swine, are raised for profit. For beef cattle, for example, it is preferred that the animal attains an optimum endpoint of tissue growth for it to be the most profitable. For a replacement dairy heifer, for example, it is preferred to minimize fat deposition in udder while maximizing bone, organ and muscle tissue. Increasing fat deposition in udder decreases heifers lifetime milking production potential. When considering the optimum endpoint of tissue growth and the optimum rate of growth, it is important to note that the weight at which animals obtain the same chemical composition differs depending on the age, the skeletal size, the sex, or the maturity of the animals. Hence, chemical composition of the animals can be different even when the weight of the animals is the same. Based on their own visual prediction and days on feed of the average meat quality grade or specification for the cattle in a pen, a feedlot manager may sell the entire pen of cattle at one time, for example. As a consequence, a proportion of the beef cattle may have been overfed past optimal fat deposition, whereas some cattle have not been fed to their genetic growth potential or maturity.
It is known in the art that English heifers are very easily overfed because they fatten readily at a light weight. However, Salers, Charolais, and other Continental breeds generally show their best carcass quality characteristics at much heavier weights than English breeds. Thus, some of the cattle may not be marketed at their optimum economic tissue endpoint, taking into consideration live and carcass prices for the cattle, incremental cost of gain to feed the cattle, and discounts for under or oversized carcasses, insufficient, and excess carcass fat on the cattle.
Work done by Dr. John Brethour (The Composition of Growth in Beef Cattle in Honor of Dr. Rodney L. Preston,” Texas Tech University, Lubbock, Aug. 2, 1996) and studies completed at Kansas State University indicated that the economic consequences of suboptimal marketing of fed cattle include: 1) costs of % 1/head/day for each day away from optimal marketing date that an animal is under or over fed (greater than 30% of the pen is marketed more than 25 days away from their optimal marketing date); and 2) results in $3.50 per hundred weight (cwt) increased cost of gain throughout the feeding period when marketing cattle greater than 28 days beyond the optimum. However, when cattle are sorted three ways, less than 3% of the cattle in a pen are marketed greater than 20 days from their optimum tissue endpoint. Thus, identifying reliable and effective techniques for optimum economic tissue endpoint will improve end-product quality and consistency and will positively impact profitability of fed cattle.
Currently, optimum endpoints of growth in feedlot animals can be achieved by predicting such things as the incremental cost of gain, the carcass quality, and the yield grade. Equations to predict incremental cost of gain and accounting for differences in net energy for maintenance requirements (NEm) of the animals, the effect of environment on maintenance requirements (NEm), the differences in body size, the implant program and feeding system have been reported in the Journal of Animal Science, Volume 70 by Sniffen et al. (1992; page 3562 to 3577) and Fox et al. (1992; page 3578 to 3596) and in the 1996 NRC model (currently known as the Cornell Net Carbohydrate and Protein System). Equations to predict carcass weight and body composition of different beef cattle breeds finished at three different endpoints have also been reported in the Journal of Animal Science, Volume 69, page 4696 to 4702, by Perry et al. (1991), in the Journal of Animal Science, Volume 72, page 1806 to 1813 by Tylutki et al. (1994), and in the journal of Animal Science, Volume 75, page 300 to 307 Perry and Fox (1997).
In addition, several reports and technologies exist in the art that address the issues of growth and management, particularly in feedlot cattle. For example, U.S. Pat. Nos. 4,733,971; 4,889,433; 4,815,042; 5,340,211; and 5,315,505 to Pratt pertain to the delivery of feed additives and inventory of drugs for feedlot cattle. U.S. Pat. No. 5,673,647, U.S. patent application Ser. No. 08/838,768, and U.S. Patent Application Publication No. 20020050248 disclose automated systems for managing and monitoring cattle. Ultrasound techniques have been developed to measure backfat in cattle by Professor John Brethour as explained in an article entitled “Use of Ultrasound to Estimate Body Composition” presented at a symposium entitled, “The Composition of Growth in Beef cattle in Honor Of Dr. Rodney L. Preston,” Texas Tech University, Lubbock, Aug. 2, 1996.
In the art of managing cattle, body weight is commonly used to project feed performance or to estimate economic profitability of the cattle. Techniques for weighing cattle are disclosed in the following U.S. Pat. Nos. 4,288,856; 4,617,876; and 4,280,448. The measurement of animal weight is used because the measuring equipment is relatively simple. However, animal weight is highly variable and thus, represents a poor indicator of animal growth. For example, body weight is sensitive to the volume of water (tissue and gastrointestinal tract content). Measurement of body water and specific gravity are indirect methods of estimating body composition, as reported in the Journal of Biological Chemistry, Volume 158, page 685 to 696 by Pace and Rathbun (1945). Using body water and nitrogen measurements of guinea pigs, the authors concluded that the water content of the lean body mass is 73% and thus should be a reasonable estimate of most species of mammals (Pace and Rathbun, 1945). The drive to measure body water generated the use of various proposed dilution techniques involving deuterium, tritium, antipyrine, and urea. The decrease in body weight due to water loss is termed “shrink” and is well recognized in the beef industry.
Not only is the amount of weight loss an animal experiences dependent upon recent water intake, but also it is dependent upon other factors, such as feed intake and stresses related to transport or sickness. Furthermore, cattle are fed differently around the world so that the percentage of empty body weight due to fat deposits (empty body weight fat percentage is sometimes referred to as empty body weight fat) and the maturity of the animals can vary dramatically from place to place. As an example, cattle of similar age, sex, breed, and weight are fed either low or high-energy ration. These cattle will both grow similar skeletal, organ, and muscle deposits. However, the cattle fed low energy ration will possess lower empty body weight fat percentage, whereas cattle fed the high energy ration will possess higher levels of empty body weight fat, have heavier weights because of additional fat, and have an eventual higher carcass dressing percentage.
Skeletal measurements of the cattle can avoid some of the transient factors associated with merely measuring the weight of the animals discussed above because changes in an animal's skeleton are independent of feed and/or water intake and transient environmental stress. As an animal grows and metabolizes nutrients, tissues are deposited through the following sequential series from first to last: nervous system, bone tissue, organ tissue, muscle tissue, and fat. In addition, tissues are deposited from the cranial to caudal region of the animal from first to last: head, neck, thorax, rump, loin, and rib area. Bone tissues that are deposited as skeletal structure regulate muscle deposition, red blood cell production, and various immunological factors and can, therefore, be a suitable determining factor of an animal's growth potential. Furthermore, skeletal measurements are not influenced by water loss or adequacy and are, therefore, a more adequate method to define the body size of the animal. In addition, the author's own research has shown that skeletal pelvic height has a high correlation to finished carcass weight for the animal compared to entry and finished weights for cattle fed over a 70-day period.
Physical measurements including pelvic measurement can be used to estimate animal characteristic, such as potential skeletal and muscle development. Typical parameters used in such estimates are hip height and width, shoulder width, and body length. Measurements of these parameters can be used to calculate shoulder muscle to bone ratio, rump muscle to bone ratio, and musculoskeletal development per unit height and length. It is believed that skeletal size or hip height of cattle can be correlated with the ultimate carcass weight of the cattle fed for a 70-day period. It is also believed that the shoulder height and the body length of cattle can be used to determine the potential average daily gain and feed conversion to final body weight of the cattle.
Unfortunately, making manual measurements of the cattle's shoulder height and body length are time consuming and less reliable. Moreover, determining points on the cattle for making such manual measurements are not well defined on the 3-dimensional animals. It is known in the art to use a conventional 2-dimensional video camera to obtain an image of the animal. The image taken with the 2-dimensional video camera, however, is not particularly useful for determining the skeletal trunk size of the animal. The image includes body mass from muscle and fat and can be confounded by lighting conditions and the hide color of the animal, for example, making it difficult to differentiate the body tissue composition (bone, muscle & fat) of the animal. For example, the anatomical juncture of the neck with the shoulder (i.e., major tubercle of humers or “point of shoulder”) is not well defined in such an image made with a 2-dimensional video camera because muscles in this anatomical region of the neck make it difficult to distinguish the skeletal elements of the major tubercle of humerus.
Another method of measuring animals uses ultrasound technology. Suitable teachings of measuring animals with the ultrasound technology are disclosed in WO99/67631, AU744213, AU449219, and CA2335845, which are incorporated herein by reference in its entirety. The reader is also referred to the following references that describe techniques for measuring animals: U.S. Pat. Nos. 4,745,472; 5,483,441 and 5,576,949, CA 2216309; and JP 10206549.
Although the techniques discussed above are useful, feedlot managers or operators are constantly seeking to improve measurement and management techniques for animals. Accordingly, a need exists in the art for accurate techniques to measure the skeletal structure of animals that can enhance a feedlot manager's ability to manage the animals to an optimum economic endpoint, thus avoiding discounts for too much fat and outsized carcasses and avoiding the economic consequence of suboptimal marketing of cattle (e.g., increased cost of gain).
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.